If $A$ and $B$ are not disjoint sets, then $n(A \cup B)$ is equal to
$n(A) + n(B)$
$n(A) + n(B) - n(A \cap B)$
$n(A) + n(B) + n(A \cap B)$
$n(A)\,n(B)$
If $A$ and $B$ are two sets, then $A \cup B = A \cap B$ iff
If $A=\{3,5,7,9,11\}, B=\{7,9,11,13\}, C=\{11,13,15\}$ and $D=\{15,17\} ;$ find
$\left( {A \cap B} \right) \cap \left( {B \cup C} \right)$
If $A=\{3,6,9,12,15,18,21\}, B=\{4,8,12,16,20\},$ $C=\{2,4,6,8,10,12,14,16\}, D=\{5,10,15,20\} ;$ find
$C-B$
If $A=\{3,6,9,12,15,18,21\}, B=\{4,8,12,16,20\},$ $C=\{2,4,6,8,10,12,14,16\}, D=\{5,10,15,20\} ;$ find
$A-C$
Consider the sets $X$ and $Y$ of $X = \{ $ Ram , Geeta, Akbar $\} $ and $Y = \{ $ Geeta, David, Ashok $\} $ Find $X \cap Y$